Automatic furnace



1934- I F. x. LAUTERBUR ET AL 1,979,383

AUTOMATIC FURNACE Filed March 28, 1929 4 Sheets-Sheet 1 INVENTOM @zzim BY fizz A TTORNE Y4:

1934- F. x. LAUTERBUR ET AL 1,970,383

AUTOMATI C FURNACE Filed Harsh 28, 1929 4 Sheets-Sheet 2 I i 2: :INVENTORIS By @144 A TTORNEYS Aug. 14, 1934.

F. x. LAUTERBUR ET AL 1,970,383

AUTOMATIC FURNACE Filed March 28, 1929 4 Sheets-Sheet s 77M f INVENTORS BY A TTORNEYJ:

g- 1934- F. x. LAUTERBUR El AL I 1,970,383

AUT OMAT I C FURNACE Filed March 28, 1928 4 Sheets-Sheet 4 1 VENTOM: BY wxa km v 412% A TTORNEYJ '35 driving the fan with a Patented Aug. 1 4, 934

1,970,383 AUTOMATIC FURNACE Frank X. Lauterbur and Edward J. Lauterbur,

Sidney, Ohio;

Wilhelmina S. Lauterbur and Leo V. Lauterbur executors of said Frank X.

Lauterbur, deceased Application March 28, 1929, Serial No. 350,765 8 Claims. (01. 110-101) Our invention relates to furnaces, especially those for heating plants'in domestic establishments.

While the art of automatic furnace stoking and control has been extensively developed, the equipment heretofore made has been particularly for use with large heating plants such as are required for the boilers of factories, and there are many conditions in a domestic heating plant which require apparatus of different types, and controls therefor operable on different principles. We have, at the outset, the broad idea of an automatic furnace which does not require the services of an attendant, and which, therefore, 16 may be installed in homes where the owners are not necessarily possessed of engineering ability.

Most automatic stoking equipment has been designed with controlling apparatus based on the heat produced in the furnace, but, while my pre- 20 ferred control has an auxiliary incidental control based on a thermal element positioned so as to become effective with variations of temperature near the lower limit line of the fuel in the furnace, it is broadly the object of our invention to provide a volume control which regulates the supply of fuel to the fire in "accordance with the volume of fuel within the furnace. It is one of our objects, inone preferred arrangement, to provide a fan for forced draft which is controlled by a '80 thermal element located near the grate line' so that when the level of fuel is low and there is danger of burning or melting the grates, the air blast is automatically shut off. This may .be provided in several different ways; in one system by clutch from the stoker motor controlled by the thermal element near the furnace grate lines. The problem of feeding fuel to a furnace from an underfeed conveyor has been greatly com- 40 plicated in previous installations by provision of conveyors having the greatest tendency to block at positions removed from the source of power. In order to avoid such a tendency to block, it is one of our objects to provide a conveyor in which the greatest tendency to block is located close to the source of power so that the greatest strain on the apparatus occurs where the power is greatest, and once having passed the position of greatest strain the fuel flows readily through a conduit which flares out, and thus provides a less restricted passage the farther the fuel is moved away from the driving end of the apparatus.

It is another object of our invention to'provide a volume control which may be adjustable for 56 uiiferent seasons, so that while in the coldest weather conditions may be such that a heavy bed of fuel is required, in warmer weather a lighter bed may sufiice.

In order to simplify the removal of ashes from the furnace, it is our object to provide an ash conveyor operated by the same power which drives the feeding device. In combination with such a conveyor, it is an object of our invention to. provide a depressed container for receiving the ashes from the conveyor.

Whilewe provide controls for automatically regulating the burning of the fire, separate and distinct from the ordinary house thermostatcontrol, it is within the contemplation of our invention to regulate the drafts for the furnace from a house thermostat which not only may augment the nicety of the regular controls, but which may be so arranged to regulate the path of the oxidizing air currents through the fire bed.

The above and other objects to which reference will be madein the ensuing disclosure we accomplish by that certain combination and arrangement of parts of which we have shown several preferred modifications.

Referring to the drawings":

Figure 1 is a side elevation of one arrangement of furnace and stokingapparatus.

Figure 2 is a front elevation of the arrangement shown in Figure. 1.

Figure 3 is a side elevation of the combination l3 shown in Figures 1 and 2 with par-ts broken away 'and in section revealing the internal structure.

Figure 4 is a horizontal cross section through the furnace and stoker along the line 4--4 in Figure 2. 00

Figure 5 is a detail view with parts in sect-ion which would correspond with Figure 3, but showing a different arrangement for volume control.

The furnace illustrated is of the ordinary hot air type, having an exterior shell 1 and a fire pct 2. The grate bars which support the bed of coals are indicated at 3, and in the center of the grate we have shown the discharge portion 4a of the fuel supply conduit which, as will benoted, is of flaring shape thereby offering less and less resistance to the fuel as it passes from the intake end 4 of the conduit to the discharge portion 4a, which opens upwardly a considerable distance above the grate, and from which the fuel ordinarily tumbles over onto the grate bars, or the bed of coals supported thereon.

The feedconveyor is of novel type, having a shaft 5, which carries worm sections 6 and narrower sharper breaker bars 7. The drive for the feed screw is best illustrated in Figure 2. An 1 0 electric motor 8 is provided, which has a pinion 9 which engages and drives a gear 10 mounted on a shaft 11. The shaft 11 carries a worm 12 which engages a worm gear 13 mounted on the shaft .5. A clutch 14 is arranged with a lever acted upon by a. magnet 15 which throws the clutch in and out, and the fan 16 may thus be driven in response to the electromagnetic control. The shaker bar 1''! shown in Figs. 1 and 4 connects to slide 17a, which by pitman 17b connects to gear 170 meshing with pinion 17d on the shaft of the fan 16, so that the grate is shaken only when the fan runs.

Referring to Figure 3 a bevel pinion 18 mounted on the screw shaft 5 engages a bevel gear 19. The gear 19 ismounted on a vertical shaft 20 which carries a large sprocket wheel 21, which drives the ash drag link conveyor 22. The discharge from the ash conveyor is a chute 23 which discharges into an ash can 24 seated within a pit 25 in the furnace room floor.

The fuel hopper is indicated at 26 and as shown in Figure 1 it will preferably be provided with a crusher bar 27, which may be suitably driven from the train of gears driving the feeding screw.

The volume control is provided in the combination shown in Figures 1 to 4 by a spreading member 28 located in the path of fuel from the feed hopper. The member 28 is mounted on arod 29 which extends up through a sleeve 30 with a member 29 at its top by which a switch 31, connected to motor 8 by wires 31a and 31b (Fig. 2) may be actuated by the elevation of the rod, thereby opening the circuit'to stop the motor 8 at maximum fuel height, or closing the circuit to start the motor at minimum fuel height.

The furnace may, as indicated in Figure 3 have a casing header 32 with draft dampers 33 asso-v ciated therewith, which may be controlled by a house thermostat, but since the controls for such dampers are ordinarily well known in the art no further reference will be made to any preferred type of thermostatic control. The thermostat 34 is located near the horizontal plane of the grate as shown in Fig. 3, and has its two elements held together, closing a circuit through the magnet 15 by way of the wires 34a and 34b as seen in Fig. 2, so that the magnet 15 acts through the lever as before described to hold the clutch 14 in engagement for operating the fan 16, unless the temperature near the grate line, due to fall of the fire level, drops below a certain minimum, upon which the thermostat elements separate, breaking the circuit so that the clutch 14 is no longer held in engagement, and the fan is stopped. This prevents blowing the fire when it is so low that the grate and other parts might be injured thereby. As the grate shaker 1''! is operated only when this clutch 14 is engaged, the fire is not shaken when it is so'low that it might be extinguished by shaking. The rate of buming depends, in addition to the nature of the fuel, upon the amount of blowing and shaking. The amount'of shaking influences the height of fuel bed, which influences the rate of falling of fuel from the supply overinlet 4a to the fire bed, which blocks this fallof fuel more or less as it is higher or lower.

In Figure 5 the spreader member 28a is carried on a rod 29a, which extends down throughsleeves 30a to actuate a switch 31a, which in a marmer similar to the operation of the switch 31 of the other example, controls the operation of the motor driving the automatic stoker. The

-or the corresponding member of the element of our apparatus disclosed member 29 that operates the switch 31 is adjusted up or down on the rod 29 connected to the element 28 in the fuel inlet 4a, according to weather conditions. The higher the member 29 is adjusted, the less will be the accumulation of fuel above inlet 4a, and the less will be the fall of fuel to the fire bed, with consequent decrease in fire bed, and greater tendency to stop the fan and the ash shaker, which will result in slower burning. The ash removal from the pit will be proportional to the fuel supply, since the ash conveyor 22 is operated only as long as the fuel supply conveyor operates. It will be seen'therefore that the single adjustment of the member 29',

28a in Fig. 5, adjusts the operation of all of the devices. When this member is adjusted lower, the fuel accumulation at inlet 4a is increased, with more fall of fuel to the fire bed, increase of depth of fire bed, and more continuous operation of the blower and ash shaker, and consequent faster burning. The rate of removal of ashes will proportionately increase. As element 28 or 28a is in fuel that is not burning, and protected by a considerable volume of this fuel all around it between it and the fire bed, this element is subjected to but little destructive influence, and its operative connection also is far removed from the fire bed, in either example.

While We have not gone into great detail in describing or illustrating the several modifications herein, it will be apparent that a wide range of structural changes will occur to those skilled in the art without departing from the principle of our invention.

Having thus described our invention what we claim as new and desire to secure by Letters Patent, is:-

1. In an automatic furnace comprising a firepot and a fuel supporting surface, a mechanical stoker including a fuel supply conduit entering said furnace below said surface and discharging above said surface, a fan having a discharge outlet under said surface, mechanism for forcing fuel in through said conduit, means foroperating said 120 mechanism and said fan together comprising a disconnectible operative connection between said operating means and the fan, thermally operated control means near said fuel supporting surface, and a connection from said thermally operated 125 control means to said disconnectible operative connection whereby the fan is disconnected from the operating means or connected thereto according to temperature conditions near said surface independently ofthe operation of said mecha- 'nism.

2. In an automatic furnace comprising a firepot and a fuel supporting surface, a mechanical stoker including a fuel supply conduit entering said furnace below said surface and having a discharge portion extending a material distance above said surface, an element adjacent to said discharge portion raised or lowered in response to increased or diminished accumulation of fuel above said discharge portion, -mechanism for forcing fuel in through said conduit, operative connecting means whereby the raising or lowering of said element stops or starts said mechanism, a fan discharging into said furnace below said surface, a disconnectible operative connection 1 5 between said fan and said mechanism, thermally operated control means near said fuel supporting surface, and a connection from said control means to said disconnectible operative connection whereby the fan is disconnected from said 150 mechanism or connected thereto according to temperature conditions near said surface independently of the operation of said mechanism.

3. In an automatic furnace comprising a firepot and a fuel supporting surface, a fuel feed conduit entering said furnace below said surface and having its delivery outlet a material distance above said surface, a spreader member above said outlet adapted tospread the fuel coming from the outlet outward and downward onto said surface and to be raised or lowered in response to increased or diminished accumulation of fuel above said outlet, mechanism for forcing fuel in through said conduit and operative connecting means whereby the raising or lowering of said spreader member stops or starts said operating mechanism.

4. In an automatic furnace comprising a firepot and a fuel supporting surface, a fuel feed conduit, an air inlet, and an ash chute extending into the furnace under the fuel supporting surface, the conduit having a discharge portion extending a material distance above said surface, conveying means in the chute and conduit, respectively, operating mechanism common to both conveying means, a fan discharging into said air inlet, disconnectible means operatively connecting said fan with said operating mechanism, thermally operated control means near said fuel supporting surface, a connection from said control means to said disconnectible means whereby the fan is disconnected from the operating mechanism, or connected thereto, according to temperature conditions near said surface, a motor driving said mechanism, an element disposed at the outlet of the fuel feed conduit discharge portion, raised or lowered in response to increased or diminished accumulation of fuel at said outlet, and means controlling the operation of said motor and operatably related to said element whereby the motor is stopped in response to the rise and started in response to lowering of said element.

5. In an automatic furnace comprising a firepot and a fuel supporting surface, a fuel feed conduit, an air inlet, a fan discharging into said air inlet, and an ash chute extending into the furnace under the fuel supporting surface, the conduit having a discharge portion extending a material distance above said surface, said surface comprising a shakable grate around said discharge portion, an operative connection from said fan to said grate whereby said grate is shaken when said fan is operating, conveying means in the chute and conduit, respectively, operating mechanism common to both conveying means, disconnectible means operatively connecting said fan with said operating mechanism. thermally operated control means near said fuel supporting surface, a connection from said controlmeans to said disconnectible means whereby the fan is disconnected from the operating mechanism, or connected thereto, according to tem peratur'e conditions near said surface, a motor driving said mechanism, an element disposed atv the outlet of the fuel feed conduit discharge por-' tion, raised or lowered in response to increased ordiminished accumulation of fuel at said outlet, and means controlling the operation of said motor and operatably related to said element whereby the motor is stopped in response to the 'rise and started in response to lowering of said element. 6. An automatic furnace comprising a fuelsupply conduit having an outlet opening upwardly therein and a grate alongside of said outlet, spaced downwardly from the outlet such a distance as to support a fire bed in controlling relation to the fall of fuel from said outlet to said fire bed, a conveyor forcing fuel through said outlet, means forcing air to said fire bed, control means adjacent to said outlet, raised and lowered in response to increased and diminished accumulation of fuel in said outlet, means whereby said conveyor is started and stopped in response to lowering or raising of said control means, and controlling means adjacent to said fire bed, stopping and starting said air forcing means in response to decrease and increase in heat emanating from said fire bed.

7. An automatic furnace comprising a fuelsupply conduit having an outlet opening upwardly therein and a grate alongside of said outlet, spaced downwardly from the outlet such a distance as to support a fire bed in controlling relation to the fall of fuel from said outlet to said 1 5 fire bed, a conveyor forcing fuel through said outlet, means for forcing air to said fire bed, control means adjacent to said outlet, raised and lowered in response to increased and diminished downwardly from the outlet such a distance as to support a fire bed in controlling relation to the fall offuel from said outlet to said fire bed, a conveyor forcing fuel through said outlet, means for forcing air to said fire bed, means for shaking ashes from said fire bed, said air-forcing means and said ash shaking means being operatively connected for simultaneous operation, control means adjacent to said outlet, raised and lowered in response to increased and diminished accumulation of fuel in said outlet, means whereby said conveyor is started and stopped in response to lowering and raising of said control means, and controlling means adjacent to said fire bed, starting and stopping said air-forcing means and said ash-shaking means in response to increase and decrease in heat emanating from said fire bed.

FRANK x; LAUTERBUR. EDWARD rum-mason. 

